110. Balanced Binary Tree

Problem Statement:

Given a binary tree, determine if it is height-balanced.

For this problem, a height-balanced binary tree is defined as:

a binary tree in which the left and right subtrees of every node differ in height by no more than 1.

Example 1:

Input: root = [3,9,20,null,null,15,7]
Output: true

Example 2:

Input: root = [1,2,2,3,3,null,null,4,4]
Output: false

Example 3:

Input: root = []
Output: true

Constraints:

The number of nodes in the tree is in the range [0, 5000].
-10⁴ <= Node.val <= 10⁴

Solution:

java

public class BalancedBinaryTree {
    public boolean isBalancedTree(TreeNode root) {
        return !(isBalTree(root) == -1);
    }

    private int isBalTree(TreeNode root) {
        if (root == null)
            return 0;
        int leftHeight = isBalTree(root.left);
        if (leftHeight == -1)
            return -1;
        int rightHeight = isBalTree(root.right);
        if (rightHeight == -1)
            return -1;
        if (Math.abs(leftHeight - rightHeight) > 1)
            return -1;
        else
            return Math.max(leftHeight, rightHeight) + 1;
    }
}

110. Balanced Binary Tree #

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Example 1: #

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110. Balanced Binary Tree

Problem Statement:

Example 1:

Example 2:

Example 3:

Constraints:

Solution:

...